Tyrus, flashing blade and death boon

[Michael]

The specific question in the other thread is:

Anson Wolfe’s feat is active. If a model destroys multiple Storm Legion models with one Thresher attack, how many times does Anson’s feat trigger?

@Thresher

Thresher (* Attack) - This model makes one melee attack with this weapon against each model in its LOS that is in this weapon’s melee range, regardless of whether that model is a friendly model or an enemy model. Thresher attacks are simultaneous.

@Anson's feat "Give 'Em Hell!"

When one or more friendly Faction models are destroyed while in Wolfe’s control area by an enemy attack, immediately after the attack is resolved one model in Wolfe’s battlegroup currently in his control area can advance up to 2" and make one basic attack. Give 'Em Hell lasts for one round.

Much as with this Flashing Blade question, we need to know:

Is Thresher one attack (despite the various wording bits that says “attacks” plural), or is it a single * attack that generates multiple separate attacks, similar to how Flashing Blade is one single spell that generates multiple separate attacks?

(Various analyses and such can be found in the linked thread.)